Wednesday June 29, 2005
Thursday June 30, 2005

"Enhanced Confined Light Transmission by Single Subwavelength Apertures"
Ms. Humeyra Caglayan
Bilkent University

Humeyra Caglayan, Irfan Bulu, and Ekmel Ozbay, Department of Physics, Bilkent University, Bilkent, 06800 Ankara, Turkey We studied grating-coupling phenomena between surface plasmons and electromagnetic waves using two-dimensional metallic gratings. We present experimental and theoretical results of enhanced transmission though a subwavelength circular aperture with metallic gratings around the surface plasmon resonance frequency. This is followed by transmission studies through circular annular apertures and circular annular apertures surrounded by periodic metallic gratings. We demonstrated that 145 fold enhancement factor could be obtained with a subwavelength circular annular aperture surrounded by periodic metallic gratings. Our results showed that high transmission from a circular annular aperture with gratings was assisted by the guided mode of the coaxial waveguide and coupling to the surface plasmons. Furthermore, we showed that transmitted EM waves emerge from the aperture as a beam with a small angular divergence. The FWHM (Full width half maximum) of the transmitted beam through circular annular aperture surrounded by gratings was 6o. The experimental results agreed well with theoretical simulations.